fix: avoid passing empty string argument to skopeo when raw=false (#380)

Replace static array construction with ArrayList to conditionally add
--raw, --authfile, and --daemon-host flags, preventing an empty string
from being passed as a CLI argument.

fixes #379

Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: soul2zimate

src/main/java/io/github/guacsec/trustifyda/image/ImageUtils.java

@@ -467,47 +467,32 @@ static Operations.ProcessExecOutput execSkopeoInspect(ImageRef imageRef, boolean
     var configPath = Environment.get(TRUSTIFY_DA_SKOPEO_CONFIG_PATH, "");
     var daemonHost = Environment.get(TRUSTIFY_DA_IMAGE_SERVICE_ENDPOINT, "");
 
-    String[] cmd;
+    var cmdList = new java.util.ArrayList<String>();
+    cmdList.add(skopeo);
+    cmdList.add("inspect");
+
+    if (!configPath.isEmpty()) {
+      cmdList.add("--authfile");
+      cmdList.add(configPath);
+    }
+
+    if (!daemonHost.isEmpty()) {
+      cmdList.add("--daemon-host");
+      cmdList.add(daemonHost);
+    }
+
+    if (raw) {
+      cmdList.add("--raw");
+    }
+
     if (daemonHost.isEmpty()) {
-      cmd =
-          configPath.isEmpty()
-              ? new String[] {
-                skopeo,
-                "inspect",
-                raw ? "--raw" : "",
-                String.format("docker://%s", imageRef.getImage().getFullName())
-              }
-              : new String[] {
-                skopeo,
-                "inspect",
-                "--authfile",
-                configPath,
-                raw ? "--raw" : "",
-                String.format("docker://%s", imageRef.getImage().getFullName())
-              };
+      cmdList.add(String.format("docker://%s", imageRef.getImage().getFullName()));
     } else {
-      cmd =
-          configPath.isEmpty()
-              ? new String[] {
-                skopeo,
-                "inspect",
-                "--daemon-host",
-                daemonHost,
-                raw ? "--raw" : "",
-                String.format("docker-daemon:%s", imageRef.getImage().getFullName())
-              }
-              : new String[] {
-                skopeo,
-                "inspect",
-                "--authfile",
-                configPath,
-                "--daemon-host",
-                daemonHost,
-                raw ? "--raw" : "",
-                String.format("docker-daemon:%s", imageRef.getImage().getFullName())
-              };
+      cmdList.add(String.format("docker-daemon:%s", imageRef.getImage().getFullName()));
     }
 
+    String[] cmd = cmdList.toArray(new String[0]);
+
     return Operations.runProcessGetFullOutput(null, cmd, null);
   }
 

src/test/java/io/github/guacsec/trustifyda/image/ImageUtilsTest.java

@@ -229,7 +229,6 @@ void test_get_image_digests_single() throws IOException {
                           new String[] {
                             "skopeo",
                             "inspect",
-                            "",
                             String.format("docker://%s", mockImageRef.getImage().getFullName())
                           }),
                       isNull()))
@@ -866,7 +865,6 @@ void test_exec_skopeo_inspect() {
                             mockSkopeoConfig,
                             "--daemon-host",
                             mockSkopeoDaemon,
-                            "",
                             String.format("docker-daemon:%s", mockImageRef.getImage().getFullName())
                           }),
                       isNull()))
@@ -898,7 +896,6 @@ void test_exec_skopeo_inspect_no_config() {
                             "inspect",
                             "--daemon-host",
                             mockSkopeoDaemon,
-                            "",
                             String.format("docker-daemon:%s", mockImageRef.getImage().getFullName())
                           }),
                       isNull()))
@@ -930,7 +927,6 @@ void test_exec_skopeo_inspect_no_daemon() {
                             "inspect",
                             "--authfile",
                             mockSkopeoConfig,
-                            "",
                             String.format("docker://%s", mockImageRef.getImage().getFullName())
                           }),
                       isNull()))
@@ -960,7 +956,6 @@ void test_exec_skopeo_inspect_no_config_no_daemon() {
                           new String[] {
                             "skopeo",
                             "inspect",
-                            "",
                             String.format("docker://%s", mockImageRef.getImage().getFullName())
                           }),
                       isNull()))
@@ -1062,7 +1057,6 @@ void test_get_single_image_digest() throws IOException {
                           new String[] {
                             "skopeo",
                             "inspect",
-                            "",
                             String.format("docker://%s", mockImageRef.getImage().getFullName())
                           }),
                       isNull()))
@@ -1097,7 +1091,6 @@ void test_get_single_image_digest_empty() throws JsonProcessingException {
                           new String[] {
                             "skopeo",
                             "inspect",
-                            "",
                             String.format("docker://%s", mockImageRef.getImage().getFullName())
                           }),
                       isNull()))